Libby Trickett broke the 50-metres freestyle world record with a new time of 23.97 seconds at the Australian Olympic trials here on Saturday.
Trickett, formerly Lenton, broke the previous record of 24.09 secs set by Dutchwoman Marleen Veldhuis just five days ago at the European championships in Eindhoven.
"I never thought that I could go that fast," Trickett said of her new 50m record swim.
"I knew I was probably due for a PB (personal best) in the 50m, but I haven't been able to put it together."
It has been some week for Trickett, who became the first woman to break the 53-second barrier in setting a new world record in the 100m freestyle at the trials on Thursday.
She swam a new time of 52.88 seconds to lower German Britta Steffen's old mark of 53.30 by 0.42 secs.
"After the 100m (world record) the other night I was just so excited and happy to race the 50m, it's just awesome," the Australian said.
"It's been so emotional for me this week on all different levels, but to me the 50m is always a celebration."
Trickett lowered her own personal best time by over half a second in the 50m and joined Australian teammate Eamon Sullivan as the fastest male and female swimmers on the planet.
Sullivan broke his own world record in winning the 50m freestyle on Friday.
Teenager Cate Campbell booked herself another individual event at the Beijing Olympics with her second-place finish in the 50m in a time of 24.38. Campbell was the runner-up behind Trickett in the 100m final.